Conventionally, as the power plant of this kind, one disclosed in Patent Literature 1, for example, is known. This power plant is for driving drive wheels of a vehicle, and is equipped with an internal combustion engine and first and second rotating machines as motive power sources. This second rotating machine is a general one-rotor-type rotating machine.
Further, the above-mentioned first rotating machine is a two-rotor-type rotating machine, and includes a stator and first and second rotors. The first and second rotors and the stator are arranged in an axial direction in the mentioned order from inside. The first rotor includes first and second permanent magnet rows that extend in a circumferential direction and are arranged side by side in the axial direction. Further, the stator is configured to be capable of generating first and second rotating magnetic fields. The first and second rotating magnetic fields rotate between first and second magnetic pole rows in the circumferential direction, respectively. Furthermore, the second rotor includes first and second soft magnetic material element rows that extend in the circumferential direction and are arranged side by side in the axial direction. The first and second soft magnetic material element rows are opposed to the first and second magnetic pole rows, respectively. Further, the first and second soft magnetic material element rows are formed by soft magnetic material elements, and comprise a plurality of first cores and a plurality of second cores arranged in the circumferential direction, respectively. The circumferential positions of the first and second cores are displaced from each other by an electrical angle of π/2.
In the first rotating machine constructed as above, when the first and second rotating magnetic fields are generated by supplying electric power to the stator, the first and second cores are magnetized by magnetic poles of the first and second rotating magnetic fields and magnetic poles of the first and second permanent magnets, whereby magnetic force lines are generated between these elements. Then, the electric power supplied to the stator is converted to motive power by the action of magnetism of the magnetic force lines, and the motive power is output from the first and second rotors. Alternatively, motive power input to the first and second rotors is converted to electric power, and the electric power is output from the stator. Further, the first rotor and the second rotating machines are connected to the drive wheels, and the second rotor is connected to the crankshaft of the engine.
In the power plant constructed as above, the operations of the engine and the first and second rotating machines are controlled, whereby motive power is transmitted to the drive wheels to drive the same.